Punch-thru lock assembly

ABSTRACT

A punch-thru lock assembly for use on safes and vaults and effective to prevent the forceful removal of the cover from the lock so as to preclude unauthorized access from being gained to the inside mechanisms of the lock while the door of the safe or vault is in its closed and locked position. The punch-thru lock assembly includes a spindle having a cam wheel secured thereto by means of a key whereby the cam wheel rotates in unison with the spindle but the key is capable of being defeated so as to free the cam wheel from engagement with the spindle. The lock assembly also includes a cover which is intentionally provided with a weakened portion through which an end of the spindle may be made to pass, when the latter is forcefully removed from the lock assembly being pushed inwardly.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The present invention relates to combination locks employed on safes andvaults, and more particularly to an improvement in lock assemblies ofthe punch-thru type which are intended to be effective to preventunauthorized access from being gained to the interior of the safe orvault on which the punch-thru lock assembly is employed.

(2) Description of the Prior Art

It has long been conventional practice utilize locks for purposes ofregulating access to the interior of safes and vaults. One of the mostcommon forms of locks, which is employed for this purpose, is theso-called combination lock. The latter embodies a combination dialhaving numbers provided thereon which, when manipulated in accordancewith a pre-established sequence, causes the tumblers housed in theenclosure case of the lock to become aligned in a set pattern wherebythe bolt of the lock is moved from its locking to its unlocking positionthereby permitting the door of the safe or vault to be opened.

A number of different approaches have been tried down through the yearsin an attempt to improve the security which is afforded through theutilization of a lock on a safe or vault. Namely, a variety of methodshave been devised for use with locks in an effort to render themvirtually tamperproof. Notwithstanding these efforts, surreptitiousentry to safes and vaults remains a serious problem which all lockmanufacturers are continuously called upon to face. In this regard,quite often it is found that surreptitious entry to a safe or vault hasbeen gained as a consequence of the lock having been defeated in somefashion.

For example, it is well-known that there exist a significant number ofindividuals who possess skills which make them adept at gaining accessto the interior of safes or vaults by surreptitiously opening the lockswith which the latter are provided. These individuals commonly employfor this purpose a technique which depends for its utilization on theapplication of the human senses of hearing and/or touch. Morespecifically, the technique which these individuals employ in thisregard involves the manipulation of the combination dial of the lock inan effort to determine, be listening for the noises and/or by sensingthe vibrations which are created when the tumblers of the lock are movedin response to the rotation of the combination dial, when the tumblershave become aligned in the position thereof which corresponds to theopen condition of the lock. Thus, through the successful application ofthe aforedescribed technique such an individual is able to effect thedefeat of the lock without destroying the latter or for that matter evencausing any measurable damage thereto. Concomitantly, a breach iseffected of the security which is designed to be provided as aconsequence of the employment of the lock; namely, the paramount reasonwhy the lock is being used at all is to provide the desired degree ofsecurity, i.e., controlled access to the interior of the safe or vaultwith which the lock is used. Absent the ability of the lock to providethis degree of security, very little other justification would remainwhich would warrant the placement of a lock on a safe or vault. It isfor this reason, therefore, that all lock manufacturers must beconcerned with the matter of the relative degree of ease with which anylock manufactured thereby is capable of being defeated.

One approach which some lock manufacturers have adopted in the past toeffect a lessening of the likelihood that their locks could besuccessfully defeated through the use of the technique described in thepreceding paragraph, which is dependent on its usage for a sensing ofsound and/or touch, is to employ means operable to dampen the soundsthat are produced when the tumblers are moved in response to rotation ofthe combination dial of the lock. More specifically, the object in thisinstance is to provide a lock which embodies means operable such thatvariations in sound and feel are dampened, and moreover are preventedfrom being usefully transmitted to the individual manipulating thecombination dial of the lock. By way of illustration, one form of such alock embodying dampening means of the aforedescribed type can be founddescribed and illustrated in U.S. Pat. No. 3,106,083 to 17 Maynard.

Another approach which some lock manufacturers have taken to combat thesusceptibility of their locks being defeated through the technique oflistening to noises and/or feeling for vibration as the tumblers move isto equip the lock with time delay means. The objective here is toprovide the lock with a time delay mechanism, which is operative topermit the lock to be opened only after a pre-established time periodhas elapsed following the setting of the tumblers of the lock foropening. One such lock equipped with a form of time delay meanscomprises the subject matter of U.S. Pat. No. 3,702,551 to Blizard.

In addition to the technique described previously herein, which relieson an individual's ability to detect through sound and/or touch when thetumblers of the lock have become aligned in their open condition, thereexists another technique for surreptitiously opening a lock which alsois frequently employed by those seeking to gain unauthorized access tothe interior of a safe or vault. Reference is had here to the techniqueof punching out the spindle with which the combination dial as well asthe tumblers of the lock are cooperatively associated. Namely, what isdone is to force the spindle out through the back of the lock, wherebythe tumblers of the lock as well as the cover of the lock case areforced from, i.e., disassociated from the lock. When this occurs, thelock is rendered inoperative, such that the lock is no longer effectiveto perform its locking function. Thus, the door of the safe or vault cannow be opened so as to enable an unauthorized person to remove thecontents of the safe or vault at will. A need has therefore beendemonstrated to provide a lock embodying means which is effective toovercome the ability of the lock to be mechanically defeated by removingthe dial and punching-thru the spindle.

SUMMARY OF THE INVENTION

In accordance with a preferred form of the invention there is provided anovel and improved lock assembly which is operative to prevent theforceful removal of the cover from the lock so as to precludeunauthorized access from being gained to the inside mechanisms of thelock while the door of the safe or vault is in its closed and lockedposition. A lock in accordance with the invention includes a lock casehaving a cover suitably affixed thereto. A spindle is supported withinthe lock case so as to have one end thereof positioned in the interiorof the lock case and the other end thereof projecting downwardly of thelock case so as to be exposed to view. The exposed end of the spindlehas a combination dial suitably affixed thereto for rotation therewith.Rotation of the combination dial is transmitted to the spindle to effectthe rotation of the latter also. The spindle has a cam wheel affixedthereto intermediate the ends thereof. A spindle key is employed tosecure the cam wheel to the spindle whereby the cam wheel rotates inunison with the spindle. The spindle key is capable of being defeated soas to free the cam wheel from engagement with the spindle. The cam wheelhas cooperatively associated therewith tumbler means and lock bolt meansoperable to determine the locked and unlocked conditions of the lock.The cover of the lock case is intentionally provided with a weakenedportion axially aligned with the spindle. Assuming that the punch-thrulock assembly is in its lock condition, the effect of the forcefulremoval of the spindle through applying an axial driving force theretois to cause the defeat of the spindle key with the result that the camwheel, the tumbler means and the lock bolt means remain positionedwithin the interior of the lock case and the lock remains in its lockedcondition.

It is therefore an object of the present invention to provide a noveland improved lock for use on safes and vaults which is effective toprevent unauthorized access to be gained to the interior of the safe orvault.

It is another object of the present invention to provide such a lockwhich embodies punch-thru means which is operative to prevent the defeatof the lock.

A further object of the present invention is to provide such a lock withpunch-thru means which is operative such that should the spindle of thelock be forced therefrom the lock nevertheless still remains operativeto perform its locking function.

A still further object of the present invention is to provide such alock with punch-thru means which is operative to prevent the tumblersfrom being forced from the lock in an effort to effect the defeat of thelock.

Yet another object of the present invention is to provide such a lockwith punch-thru means which is operative to prevent the cover frombecoming disassociated from the lock case in an effort to effect thedefeat of the lock.

Yet still another object of the present invention is to provide such alock with punch-thru means which is compatible for use with mostexisting types of safes and vaults.

Yet a final object of the present invention is to provide such a lockwith punch-thru means which is relatively simple in construction, whichis easy to employ, and which is relatively inexpensive to manufacture.

BRIEF DESCRIPTION OF THE DRAWING

The FIGURE is a sectional view of a punch-thru lock assembly constructedin accordance with a preferred embodiment of the present invention andillustrated in mounted relation to the door of a safe.

DESCRIPTION OF A PREFERRED EMBODIMENT

Referring now to the FIGURE of the drawing, there is illustrated thereina punch-thru lock assembly, generally designated by reference numeral10. The punch-thru lock assembly 10 is typically mounted on the door 12of a safe or vault by means of any conventional form of fastener.

Punch-thru lock 10 includes a lock case 14 in which the internal workingmechanisms of a lock are suitably retained, in a manner which will bedescribed subsequently. The case 14 is substantially rectangular inconfiguration; case 14 having a plurality of side walls and a firstclosed end wall which are suitable joined together so as to preferablyform an integral structure. A removable punch-thru lock case cover 16effects the closing of the open second end of case 14. The lock casecover 16 is secured to the lock case 14 through the use of any suitabletype of fastener.

The punch-thru lock 10 further includes a spindle 18 which has a firstend 20 thereof supported for rotation within the interior of the lockcase 14. The second end 22 of spindle 18 projects outwardly through lockcase 14 and is of sufficient length so as to be capable of projectingbeyond the outer surface of door 12. The exposed second end 22 of thespindle 18 has a combination dial 24 secured thereon in the conventionalmanner. The combination dial 24, which bears numerals (not shown) andindicia 26 thereon, is designed to be grasped and manipulated in awell-known manner for purposes of effecting the opening of the lock 10thereby permitting the door 12 of the safe or vault to also be opened.To this end, the combination dial 24 is secured to the spindle 18 in amanner whereby rotation of the combination dial 24 is transmitted to thespindle 18.

A cam wheel 28 is mounted on spindle 18 to intermediate the endsthereof. Cam wheel 28 is defeatedly secured to the spindle 18 throughthe use of a spindle key 30. The spindle key 30 is received in alongitudinally extending slot 32 formed in the circumference of spindle18. In addition, the spindle key extends into a slot, not shown, in thehollow interior of the cam wheel 28; cam wheel 28 being provided with ahollow interior suitably dimensioned so as to permit the spindle 18 tobe received therewithin with a sliding fit and the spindle key receivingslot being formed in a side wall of the hollow interior of the cam wheel28. Thus, the spindle key 30 is operative to secure the cam wheel 28 tothe spindle 18 whereby the cam wheel 28 will rotate in unison with thespindle 18 as long as the spindle key 30 remains positioned in the slot32 of the spindle 18 and the aligned slot provided therefor in the camwheel 28.

Spindle 18 preferably has a spindle retainer 34 cooperatively associatedtherewith. The spindle retainer 34 is utilized in the course of mountingthe cam wheel 28 on the spindle 18 and then positioning the latter inthe lock case 14. Spindle retainer 34 is preferably threadedly engagedon the end 20 of the spindle 18 after the cam wheel 28 has beenpositioned on the spindle 18 but before the spindle key 30 has beeninserted in the slot 32 of the spindle 18.

The remainder of the internal mechanism of the punch-thru lock assembly10, which is illustrated in the drawing and which remains to bedescribed, consists of the actual locking mechanism of the lock and isessentially of conventional construction. The locking mechanism may takethe form of any of the conventional structures commonly employed forthis purpose and thus it is not deemed necessary for purposes ofobtaining an understanding of the present invention for a detaileddescription of this locking mechanism to be set forth therein. Sufficeit to say, the locking mechanism includes a multiplicity of tumblers,which in accordance with the illustrated embodiment of the inventiontotal three in number, i.e., tumblers 36, 38 and 40. Obviously a greateror lesser number of tumblers could be employed in the punch-thru lockassembly 10 without departing from the essence of the invention. Thetumblers 36, 38 and 40, in a manner well-known to those skilled in theart, each carry a gate which is designed to cooperate with a fence 42.The fence 42, in turn, is cooperatively associated in conventionalfashion with the lock bolt 44. The lock bolt 44 is cooperativelyassociated with the cam wheel 28 whereby movement of the lock bolt 44can be effected under the control of the cam wheel 28. Morespecifically, a portion of the lock bolt 44, under the bias of spring46, is drivingly engaged with the cam wheel 28 and the tumblers 36, 38and 40 whereby through the rotation of the combination dial 24 the lockbolt 44 can be moved from its extened locking position to its withdrawnunlocking position. In accordance with the preferred embodiment of theinvention, one end of the spring 46 engages a portion of the lock bolt44, while the other end surrounds a portion of a threaded fastener 48.The latter is threadedly engaged in the lock bolt 44 and is operative toeffect the regulation of the spring force being exerted by the spring46. For purposes of obtaining a better understanding of the mode ofoperation of the lock bolt 44, reference may be had, for example, to thetwo issued U.S. Patents to which reference has previously been madeherein.

Completing the description of the punch-thru lock assembly 10constructed in accordance with the disclosed embodiment of the presentinvention, the lock case cover 16 is intentionally provided with aweakened portion 50. The weakened portion 50 is located in the casecover 16, so as to be axially aligned with the spindle 18. Consequently,should an attempt be made to gain surreptitious entry to the safe orvault equipped with the punch-thru lock assembly 10 of the presentinvention by removing the combination dial 24 from the spindle 18 andthereafter applying a force of suitable strength to the end 22 of thespindle 18 to cause the latter to be driven into the lock case 14, theend 20 of the spindle 18 operates to punch a hole through the weakenedportion 50 provided for this reason in the lock case cover 16. Thebreaking out of a portion of cover 16 permits the spindle 18 to movelongitudinally relative to the lock case 14 leaving the remainder of thelock assembly 10 intact; i.e., the spindle will also move longitudinallyrelative to the internal mechanisms including the cam wheel 28 and thetumblers 36, 38 and 40.

In conventional lock assemblies the cam wheel is threaded directly on tothe spindle. In the punch-thru lock assembly 10 constructed inaccordance with the present invention the cam wheel 28 is detachablymounted on the spindle 18 through the use of the spindle key 30.Consequently, in lock assemblies of conventional construction, when thespindle thereof is driven into the lock case, the cam wheel is carriedtherewith causing the tumblers of the lock as well as the lock casecover to be forcibly removed from the lock. By way of contrast, thespindle 18 of a lock in accordance with the present invention will slidethrough the cam wheel 28, striking the weakened portion 50 of cover 16and pass therethrough. The remainder of the internal mechanism of thelock assembly 10, including the cam wheel 28 and the tumblers 36, 38 and40, remain intact in their respective original positions.

The weakened portions 50 of the lock cover case 16 is preferably createdby milling the inside surface of cover 16 to within 0.015 inches ofbreaking through. In addition, the weakened portion 50 is preferablyformed so as to be equivalent in diameter to the inside diameter of thecam wheel 28 so as to preclude use of a punch 50 to force the cam wheel28 out of position after forcible removal of spindle 18. It should benoted that the disengagement of the cam wheel 28 from the spindle 18occurs from the fact that, as the spindle 18 is driven into the lockcase 14, the spindle retainer 34 functions to cause the spindle key 30to move with the spindle 18. Thus, the spindle key 30 remains positionedwithin the slot of the spindle 18 and slides out of the slot in the sidewall of the hollow interior of the cam wheel 28.

For purposes of clarification, the added steps involved in the assemblyof the spindle 18, the cam wheel 28, the spindle key 30 and the spindleretainer 34 are as follows. First the proper length of the spindle 18 isdetermined by inserting the spindle 18 into the cam wheel 28 until thecombination dial 24 rests against the outer surface of the door 12 ofthe safe or vault. Then an allowance of 1/4 inch is made from theshoulder of the cam wheel 28, with the spindle 18 then being removed andthe excess length of the spindle 18 thereafter being cut off. Thespindle 18 is then placed into the cam wheel 28, and the spindleretainer 34 is screwed on to the end 22 of the spindle 18 until thespindle retainer 34 is snug. Thereafter, the spindle retainer 34 isbacked off until the internal slot in the cam wheel 28 is aligned withthe slot 32 of the spindle 18 and a slot provided in the spindleretainer 34. The spindle key 30 is then inserted into the three alignedslots. The assembly of the cam wheel 28, and the spindle retainer 34 onthe spindle 18 is thereby effected with the spindle key 30.

Thus, in accordance with the present invention, there has been provideda novel and improved lock for use on safes and vaults which is effectiveto prevent unauthorized access to be gained to the interior of the safeor vault. The lock of the present invention embodies punch-thru meanswhich is operative to prevent the defeat of the lock. In accordance witha preferred form of the invention, the lock is operative such thatshould the spindle of the lock be forced therefrom the lock neverthelessstill remains operative to perform its locking function. The lock of thepresent invention is thus operative to prevent the tumblers from beingforced from the lock in an effort to effect the defeat of the lock.Moreover, a lock in accord with the present invention is operative toprevent the cover from becoming disassociated from the lock case in aneffort to effect the defeat of the lock. In addition, the lock of thepresent invention is compatible for use with most existing types ofsafes and vaults. Finally, in accord with the present invention a lockhas been provided which is relatively simple in construction, easy toemploy, and relatively inexpensive to provide.

While only one embodiment of the invention has been shown, it will beappreciated that modifications thereof, some of which have been noted inthe preceding description, may readily be made by those skilled in theart. Accordingly, it will be understood that the appended claims areintended to cover the modifications specifically referred to herein aswell as all other modifications which fall within the true spirit andscope of the invention.

What is claimed is:
 1. A lock assembly comprising:housing means, saidhousing means having an access opening in at least one end thereof;spindle means supported within said housing means for rotation relativethereto, said spindle means having an axis and a first end locatedwithin said housing means, the second end said spindle means projectingoutwardly of said housing means so as to be exposed to view; cam wheelmeans supported on said spindle means intermediate the ends thereof;spindle key means detachably securing said cam wheel means to saidspindle means whereby rotation of said spindle means is transmittedtherethrough to said cam wheel means to cause said cam wheel means torotate in unison with said spindle means, said key means permittingaxial motion of said spindle means relative to said cam wheel means;tumbler means cooperatively associated with said cam wheel means, saidtumbler means being movable in response to rotation of said cam wheelmeans between a first position corresponding to the locked condition ofthe lock assembly and a second position corresponding to the unlockedcondition of the lock assembly; lock bolt means cooperatively associatedwith said cam wheel means and said tumbler means, said lock bolt meansbeing movable between a first position when said tumbler means is insaid first position thereof wherein said lock bolt means is operative toeffect the establishment of the locked condition of the lock assemblyand a second position when said tumbler means is in said second positionthereof wherein said lock bolt means is operative to effect theestablishment of the unlocked condition of the lock assembly; and covermeans secured to said housing so as to at least in part cover saidaccess opening, said cover means having a weakened portion axiallyaligned with said spindle means, said spindle means first end breakingthrough said weakened portion when said spindle means is forcibly drivenaxially into housing means.
 2. A lock assembly as defined in claim 1further comprising:combination dial means supported on said second endof said spindle means so as to be available for grasping and rotatingthereby to impart rotation therethrough to said spindle means.
 3. A lockassembly as defined in claim 1 further comprising:spindle retainer meansfastened on said first end of said spindle means, said spindle retainermeans including a spindle key means receiving slot, said spindleretainer means being operative to effect the disassociation of saidspindle key means from said cam wheel means and thereby from saidspindle means when axial motion is imparted to said spindle means.
 4. Alock assembly as defined in claim 1 wherein said housing meanscomprises:a substantially rectangular enclosure formed by the joiningtogether of a multiplicity of side walls and an end wall to create anintegral structure.
 5. A lock assembly as defined in claim 1 whereinsaid spindle means comprises:an elongated spindle having alongitudinally extending slot formed in a circumference thereof forreceiving therein said spindle key means in sliding relation thereto. 6.A lock assembly as defined in claim 1 wherein said cam wheel meanscomprises:a cam wheel having a hollow interior and slot means formed inthe side wall of said hollow interior for receiving said spindle keymeans therein with a sliding fit.
 7. A lock assembly as defined in claim1 wherein said spindle key means comprises:an elongated key memberengageable jointly with said cam wheel means and said spindle means. 8.A lock assembly as defined in claim 1 wherein said cover meanscomprises:a cover fastened to said housing means, said weakened portionof said cover being formed by milling away the surface of a section ofsaid cover.
 9. A lock assembly as defined in claim 5 wherein said camwheel means comprises:a cam wheel having a hollow interior and slotmeans formed in the side wall of said hollow interior for receiving saidspindle key means therein with a sliding fit.
 10. A lock assembly asdefined in claim 9 wherein said spindle key means comprises:an elongatedkey member engageable jointly with said cam wheel means and said spindlemeans.
 11. A lock assembly as defined in claim 10 furthercomprising:spindle retainer means fastened on said first end of saidspindle means, said spindle retainer means including a spindle key meansreceiving slot, said spindle retainer means being operative to effectthe disassociation of said spindle key means from said cam wheel meansand thereby from said spindle means when axial motion is imparted tosaid spindle means.
 12. A lock assembly as defined in claim 11 whereinsaid cover means comrises:a cover fastened to said housing means, saidweakened portion of said cover being formed by milling away the surfaceof a section of said cover.
 13. A lock assembly as defined in claim 3wherein said spindle means comprises:an elongated spindle having alongitudinally extending slot formed in the circumference thereof forreceiving therein said spindle key means in sliding relation thereto.14. A lock assembly as defined in claim 13 wherein said cam wheel meanscomprises:a cam wheel having a hollow interior and slot means formed inthe side wall of said hollow interior for receiving said spindle keymeans therein with a sliding fit.
 15. A lock assembly as defined inclaim 14 wherein said spindle key means comprises:an elongated keymember engageable jointly with said cam wheel means and said spindlemeans.